The present invention relates to a coating composition for glass containers, which is coated onto the outer surface upon recycling glass containers for beer, juice, mineral water, etc. to enhance the appearance as well as masking scratches.
The glass containers for beer, juice, mineral water, etc. are repeatedly used by a collection system. When repeatedly using these bottles, scratches can generate on the outer surface due to mutual rubbing of bottles in the filling and distribution process to injure the appearance and to decrease the commercial value of bottled beverages. Upon recycling, therefore, it is necessary to coat a coating agent onto the portion of scratches, thus masking the scratches inconspicuous and enhancing the appearance at the same time. The portions of bottles violently generating the scratches are approximately fixed; for example, in the case of common beer bottles in Japan, the generation of scratches are violent at the positions of 1 to 2 cm, 5 to 7 cm and 13 to 15 cm from the bottom. For this reason and other various conditions, partial coating such as two or three-stripe coating or the like, wherein the coating liquor is applied only onto the portions of violent scratches, is generally carried out. However, the scratches sometimes generate at positions other than those fixed positions, thus improvement in the working process is required for beautifully finishing even such portions.
In order to cope with such problems, some coating compositions for the scratches of glass containers have so far been proposed. For example, in Japanese Unexamined Patent Publication No. Sho 57-179053, a composition using dimethylpolysiloxane together with aminomethylpolysiloxane is disclosed. Also, in Japanese Unexamined Patent Publication No. Sho 59-145259, a composition having liquid paraffin as a major ingredient and using small amounts of higher alcohol fatty acid ester and polyhydric alcohol fatty acid ester in combination is disclosed. Furthermore, in Japanese Unexamined Patent Publication No. Sho 62-128951, a composition containing acetylated glycerine fatty acid ester as an essential ingredient has also been disclosed. While these are favorable compositions for said partial coating processes, they are unsuitable in several points when considering overall coating process by the shower or spray method of coating liquor or with sponge aiming at the improvement in the partial coating process and the beautiful finishing of overall bottle surface. If considering the coating liquor for overall coating, such matters that it dries rapidly, that it does not allow slippage where handled, that it does not adversely affect the label (exudation and easy stripping off) and that it allows good transportability (no rubbing in the printed area of label) are desired in addition to the performance desirable for the coating liquor by the conventional system (masking property, appearance, non-tackiness, water resistance and washing property).
The purpose of the invention is to provide a coating composition for glass containers having solved said problems.
As a result of diligent investigations for obtaining a coating composition for glass containers having solved said problems, the inventors have reached the invention.